


Take Responsibility!

by syac



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: 18+, Dubious Content, Illogical setting, M/M, No Beta, Senkuu and Tsukasa are friends, Smut, Soft Tsukasa, Spoiler characters!, Stone World AU, Story created after chapter manga ch86, Sweet ending(?), TKSTsukasaSenkuuMonthJan2020, TKSevents, TheKingdomofShipping, TsukaSen – Free For All, Tsukasa being OOC in the end, TsukasaSenku, Tsukasen, bottom!Senkuu, finger puppets, non-scientific, spoilers manga, stone world, top!Tsukasa, 司千
Language: English
Status: Completed
Published: 2020-01-29
Updated: 2020-01-29
Packaged: 2021-02-27 15:54:02
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 5,750
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22465981
Author URL: https://archiveofourown.org/users/syac/pseuds/syac
Summary: Week 4 TsuSen month.Tsukasa didn't understand what had happened. One second he's happily playing with the small plush. The next second Senku let out a small cry.
Relationships: Ishigami Senkuu & Shishiou Tsukasa, Ishigami Senkuu/Shishiou Tsukasa
Comments: 10
Kudos: 223
Collections: TsukasaSenkuuMonth - January 2020





	Take Responsibility!

**Author's Note:**

> **READ THE MANGA.** Spoilers, at least read up to chapter 86. 
> 
> **Note:** Written for TsuSen Week 4 (23rd-31st), prompt: **Free for all** / previous prompts in TsuSen month.
> 
> This is purely a work of fiction and does not imitate nor reflect on any real-life story. Neither does it depict on the fictional character’s true personality properly. This fic has not been beta-read. BEWARE of tenses.
> 
>  **Warning 1:** There is **smut**. _Do not read if you’re not of legal age!_  
>  **Warning 2:** Don't understand?/ignored warning tags?/LIKE? Don't READ.

It was a bright summery day within the greenery woods of the new stone age world. Shishiou Tsukasa lightly yawned as he walked down the familiar pathway back to the simple village. No, it is not a simple village anymore. The village is now a busy part of the Kingdom of Science. It belongs to an ambitious young man, Ishigami Senku. The 'Senku' that Tsukasa had known was constantly inventing and making evolutionary stuff for the sake of humanity. Tsukasa smiled at the antics of the younger man. Or perhaps, they could both be at the same age now.

Ever since Tsukasa had been frozen, petrified and reawakened again, two years have at least gone by. His own amber eyes had woken up to a smirking scientist and to his own delight, the sight of his own little sister, Mirai. Having been known as the strongest primate from the past, Tsukasa got back on his feet in no time. He smiled and hugged his little sister, happy to be reunited with her again. Tsukasa even hugged Senku, thanking him for saving the taller male, for saving his sister and for saving him from death.

Tsukasa shall definitely fulfill the promise he made from the very start. He had also confirmed his promise once more before the fight with Hyouga. This time round, the taller male reaffirms his promise again. He will protect Ishigami Senku and will also take care of the food supply as promised. This resulted in him currently carrying a game of large deer over his shoulder, walking towards the village.

A few friendlier people wave and say hi to him. He either comments, nod or smiles back at them. It is rather mystical that the village people were as kind-hearted as the stone people Tsukasa had previously revived. Normally, people are quick to point fingers and force their hatred views onto the ones that did wrong. To Tsukasa, it is refreshing and also a relief that the kind people are willing to forgive him on what he have done and had given him a second chance. They even forgave Hyouga and Homura!

Tsukasa left the game deer into the hands of the chefs inside the kitchens section within the village. The person now in charge is Francoise, a humble servant of a previously rich navigator, Ryuusui. Francoise thanked Tsukasa for the catch of the animal and mentioned that his sister Mirai, and Yuzuriha were waiting for him at the fabric crafts club in the village. Pondering what his little sister has been scheming, requiring the help of Yuzuriha, the taller male made his way towards the craft area.

Approaching the entrance of a small shed, Tsukasa looked around. The crafting of larger fabrics were normally held outside in more open areas. This small wooden shed's use was to hold items like simple bone needles, samples of fabric and just some storage for premade clothes. The taller male spotted his sister chatting excitedly to Yuzuriha at the only table worktop available inside the place. He walked inside to greet them. "Mirai, Yuzuriha."

Both girls turned around to meet him at the same time. The smaller of the two girls, blonde-haired Mirai beamed up happily at Tsukasa, "Big brother, you're back!"

"Yes, I'm home Mirai," Tsukasa give a small smile at his sister. Yuzuriha then gave him a smile and spoke up, "Tsukasa. Mirai-chan... she said she has a small gift for you." 

"Oh?" Tsukasa is intrigued.

"Yes, big brother! Here!" the blonde-haired girl held her arms up and uncovered her palms. The gift appears to be two very small finger-sized plushies, in simple dyed fabric. Tsukasa recognises the character plushies they represent. One of them looks exactly like Tsukasa himself, though a cuter version. The other one looks like Senku. The taller male reaches out for both of them and his little sister deposited them into his single larger hand.

"They're very well made," Tsukasa praises and looked at both girls. "What...brought this on?"

"I was testing out some leftover fabrics. I wanted to make... Taijuu-kun something," Yuzuriha whispered at the end of her sentence. "And then I thought I'll make Senku-kun something..." The meek brown-haired girl glanced over at Mirai. "Then Mirai-chan came in here to deliver some stuff. She saw what I was doing and said she wanted to make one you one too."

"I made yours, big brother!" Mirai happily grinned up at him. "I also added one of Senku's hair strands into his plushie to make the hair look shinier. Look!" The young girl enthusiastically pointed at an extra hair-line being sowed into the fabric. "Also, you can do this to these!" Mirai took the small Tsukasa plushie and pushed one of her tiny fingers into the Tsukasa plushie. It looks a bit loose on her finger. "These are finger puppets!"

"...That's nice." Tsukasa then gave a confused smile at his sister. "Mirai... how did you...no, why did you sew Senku's hair strand into the finger puppet?"

"I already said it'll make it shinier!" The little girl pouted, cheeks inflating a little bit. "Besides, it makes the plushie look more real this way, right?"

Tsukasa frowns. "And... how did you manage to get those hair strands off him?" 

Mirai made a thinking motion before answering, "He was scratching his head and I saw a few strands fell off. They looked shiny so I picked it up."

"Mirai..." the older brother frowns even further. "Don't just pick anything off the ground... it's dirty..."

"It's fine~! I even washed it with Senku's premade soap!" the little sister cheekily retorted.

"That's not the issue here... you can't just... use someone else's... stuff... on something like this..." Tsukasa sighs as he pinched his bridge of his nose while Mirai pouted at her brother.

"Um, Tsukasa-kun? I don't think there's any harm on doing something like this," Yuzuriha tries to pacify between the two siblings. "Besides, I guess if Senku-kun had known, he'll probably let her use it if it's for science or just merely to entertain younger children."

"Exactly! Senku is way more fun than you are, big brother!" Mirai cheers at Yuzuriha covering for her as she sticks her tongue out at Tsukasa. "Let's go, Yuzuriha!" Mirai declares as she drops the Tsukasa finger puppet back onto the same palm that was already holding the Senku finger puppet. "Let's ignore this _stiff_ big brother and go find Taijuu!" the little girl dragged Yuzuriha away by the arm. The taller girl gave an exasperated smile at Tsukasa while also signaling at the elder sibling that she'll take care of the younger girl.

"Stiff...big brother..." Tsukasa mourns in sorrow at his sister's dismissive attitude towards him. He let out another sigh as he looked at both the finger puppets. They are very well made and he placed his own finger inside the one that represents him. It fits snuggly on his finger. He removes it and places it in one of his personal belt sachets. Perhaps he can persuade Senku to have the scientist finger puppet. He felt bad that Mirai had stuffed the scientist's hair strand as part of the puppet without proper consent.

Tsukasa made his way to the science lab of the village. Normally there would be plenty of other people mingling about outside the lab, whether to make stuff or consult on other plans. Today, it's a bit quiet. Nobody was within sight. The taller male looked inside the laboratory and spotted the familiar scientist. He called out, "Senku."

Senku seems to be within his own thoughts as he looked through a few paper documents and switching over to check some test tubes. His back was facing towards Tsukasa. The strongest primate looked around inside. It seems like Senku is the only one inside the lab today. Tsukasa walked inside, this time slightly leaning over Senku's shoulder to see what the scientist was doing. "Senku, do you need help?"

Perhaps it was because of their closer contact, Senku finally seemed to register that Tsukasa had been calling out for him and was standing right behind him. He snapped his neck quickly towards the taller male's face before giving his usual cocky grin. "Oh, it's you. What brought you here?"

Tsukasa looked over at the paper documents on the table and at the one in Senku's hand with interest. He flickered his gaze at the test tubes before finally blinking at Senku. The taller male leant back and held a straighter posture, answering, "Oh, Mirai and Yuzuriha both made you something." He turned his head towards the documents, "You need help with those?" 

"Hmm? Nah, this is just a side project. Apparently, Chrome had found a plant I don't remember seeing in the modern era," Senku looked at the test tubes. "I just tried to decompose and analyse it to find out what it is. Though Yuzuriha did take some since she wanted to try it out as a fabric."

"Oh?" Tsukasa blinks as he brought the finger puppets out, "Do you think she used it on these?"

"Heh... as expected of Yuzuriha, her craft skills are top-notch," Senku grinned as he picked up the small plush that resembles him. There's a small glint from the hair part. The scientist squints to look a little closer. That hair colour and shine... there's no mistake, this is his own hair. "...Is that my hair in there?"

"Uh...Yes, it's Mirai...," Tsukasa hesitated before explaining. "Apparently she found your hair strands lying around. She confessed she used them to make your puppet _’prettier’_." The strongest primate paused, "...I apologise on her behalf... for using other people's things."

Senku waved Tsukasa's apology off. "Nah, it's fine. It's just a harmless idea from a kid." The scientist examined it a bit more before flickering his gaze over at the other finger puppet lying on Tsukasa's palm. Senku dropped his own puppet back and picked up the other puppet that resembles the strongest primate.

Tsukasa watched with surprise as Senku slips his own finger into the Tsukasa finger puppet. The scientist playfully waved his finger about in front of Tsukasa's eyes and teased, "I'm Shishiou Tsukasa~, the strongest high school primate~, my interest is collecting pink seashells~"

"...I do not collect seashells as an interest." Tsukasa playfully frowns. "And they're not always pink either," he tries to explain himself, yet Senku just continues to beam at him with that sly cocky grin. Tsukasa decides to fight back. He picked up the Senku plushie on his palm and gently slipped a finger in, unaware that the real Senku in front of him had subtly flinched.

"Hmm. I'm Ishigami Senku. Top scientist of this current stone world and would like to go to space one day. Even though I do not have the stamina for it," Tsukasa chuckled at the other's angry pout. The taller male waved the finger puppet around and shot a meaningful look at Senku, hinting that it was the scientist himself who started it first.

However, the scientist's face suddenly looked flushed. One of Senku's hand was gripping the table hard, the other one with the Tsukasa finger puppet had turned to a fist and was resting on the lab table. Tsukasa's eyes widened at the sight and grew concerned. He stepped nearer to the shorter male, "Senku? Are you alright?" 

Senku was inhaling at irregular intervals. What... was that sudden feeling? It's like something has been jamming between his legs... The scientist swallowed a pant as he wiped some sweat away under his chin with one arm. "Yeah... I...think so...?" 

"You sure?" Tsukasa asked, bringing the hand up to Senku's forehead, checking for a fever. "Hmm... you do seem warmer than usual..." Tsukasa looked at Senku worriedly as the scientist hiccupped. "Hmm... perhaps we should lay you down inside the observatory..." The taller male decided as he placed the hand that has the Senku puppet around Senku's waist. 

As he did that, Tsukasa had unconsciously curled his fingers inwards, applying pressure on not only Senku's waist but inside the puppet as well. Senku immediately gave a jolt and let out a groan. "N-no..." The scientist gasped. "Don't do that..."

"...But if we don't, I can't get you to the lab Senku," Tsukasa frowned, totally misunderstanding what Senku had meant. "Here, let me carry you? Piggy-back styled or... bridal styled?" The strongest primate removed his hands from Senku's waist. He curled them into fists while laying them by his sides, waiting for Senku's reply.

But Senku only groaned slightly louder. He keeled over the lab desk, trembling. This had Tsukasa on alert. "Senku!?" The strongest primate decided to discard his choice offerings. Tsukasa was about to grab the scientist but Senku shakily held out an arm in front of him, halting the taller male. "D-don't!" 

"But..."

"Stop...whatever it is you're doing!" Senku cried out, face flushed and head down on one of his arms on the desk. The scientist tilts his head slowly and looks over at the taller male, scanning him like an x-ray. His misty red eyes landed on the finger puppet in Tsukasa's hand. "That... take that off?"

"Huh?" Tsukasa raises his eyebrows at Senku's demand. He traced Senku’s sight and glanced over at his hand that had the Senku finger puppet. Touching the top with his other hand, he looked back at the scientist, "This one? Why-"

"Haaahhh!" This time the scientist wasn't able to support himself, he fell down on his knees, both hands gripping the edge of the lab desk and his forehead rested upon his hands. "S-stop doing that..." he whined with his eyes closed at the pressure sensation being applied near his stomach.

Tsukasa flinched at the shorter male's fall. He could not comprehend what Senku had meant when he kept asking the taller male to stop. Stop what? The strongest primate looked closer at Senku. Panting hard, face flushed, the trembling...could this be...?

"Senku... are you... being turned on?" The taller male sweated. What had brought this on? The shorter male's reply was a turn of his red face, away from Tsukasa. The strongest primate blinked and looked down at the Senku finger puppet on his finger.

He remembers his little sister said she added Senku's hair into the doll. Then he recalls Yuzuriha having made the puppet with leftover fabric. Senku had also mentioned Yuzuriha had taken some of that unknown plant and wanted to test it out as a fabric. Could it be...? Tsukasa lifts the Senku puppet out of his finger completely, staring at it for a few seconds before turning the doll around to check for anything out of the ordinary.

Tsukasa gazes at the shorter male again, kneeling on the ground and the breathing sounds seems to have quieten down a bit. He then looks over at the Tsukasa finger puppet. That one too, didn't seem like there's anything wrong with it either. At least, Tsukasa himself didn't feel anything different. The taller male blinked. Thinking that it couldn't have been the doll, Tsukasa slipped the Senku finger puppet back onto his finger.

A sudden large cry erupted from Senku, this time Tsukasa's eyes widened. He snapped his neck over to monitor the scientist. Although Senku was in such a poorly state, Tsukasa finds the shorter male appearing to be quite adorable right now. Amber eyes glanced down at the Senku puppet. This time he gently slid the doll out slightly, not quite leaving his finger tip. And slammed the finger puppet back into his finger, the inside hitting it right at the tip.

As suspected, this time Senku let out a mewl as his whole body slid down with a thud on the floor. The shorter male whimpers, "N-no..." A pool of heat is forming down at Senku's body. The scientist curled up, misty red eyes glaring up at the taller male. "I... I told you to stop it..." He hiccupped. "...Do something!" 

Senku's heated face has Tsukasa's heart beating rapidly. Swallowing his own saliva, the taller male quickly scooped the shorter man in his arms, earning squeak from the scientist. Tsukasa carried the shorter male to the entrance and spied around outside. Spotting no one around, he stepped out with one arm carrying Senku. The strongest primate quickly dashed and climbed the ladder, leading into the observatory.

Relieved that nobody is inside, he hastily closed and blocked the wooden doors with a piece of wood board. This should ensure nobody would come barging in. Tsukasa give a quick glance inside. There's a small deer rug on the floor and another larger piece of boar cloth over it. Senku must've slept here when he observes the stars late at night.

The taller male moves the boar cloth away to the side and gently lays Senku on the deer rug. He stood up and looked over at the panting scientist laying on the floor. Ruby eyes glistening with tears looked back up at him with a pout. Tsukasa holds his hand with the Senku finger puppet and takes a hold of the doll with his other hand.

Red eyes widened and realising what Tsukasa was about to do, Senku tries to stop the strongest primate, "No! Don't- aaahhhhh!" the scientist cried out as the feeling of applied pressure formed inside between his legs again. Senku curled inwards before scowling at the taller male standing above him, "You...bastard..."

On the other hand, Tsukasa felt like he found something precious. His eyes lit up in excitement. This must be what Senku felt, when he discovers something scientifically intriguing. "Sorry Senku... but this is... exhilarating," Senku moaned as Tsukasa pushed another thrusting motion into the finger puppet. 

"Surely... you'll want to get to the bottom of this...?"

"Yes...but not when I'm the subject- ahhhhh!" Senku groaned. "Seriously, stop it you ba-aaahhh!!" The scientist cried out. Senku threw accusing glistening eyes at the taller male standing above him. He gasps as Tsukasa repeated the motion. Again, and again. Senku was reduced into a withering mess of small pleasurable moans, silvery drool and occasional delighted gasps.

"No...no more..." The scientist panted as Tsukasa relentlessly fingered into the puppet. Senku's breathing turned vigorous as the heat concentrated towards his nether region had increased. He started moaning louder, body scrunching inwards before his back arched on the floor, mewling before cumming hard. Streams of white liquid squirted out inside his tunic, some of it leaking down his thighs and making him feel sticky. Tsukasa drank in the delicious sight of the flushed young scientist before him. Oh... and his own manhood is now waking up...

Senku groaned, half with pleasure and half in annoyance. Misty ruby eyes glowered at Tsukasa, his lips forming an unconscious adorable pout. This makes Tsukasa internally coo at the scientist more, his face blushing as what Senku would call 'a shit-eating-grin'. The scientist looks at Tsukasa's sheepish expression before ruby eyes landed at the bulge on the taller male's nether region. One of Senku's eyes twitched as he let out a deep harsh scowl, "Tsukasa...!"

The strongest primate flinched as he tries to explain himself, "Uh...well... Senku, I... s-sorry but... you were _so_ cute..." Tsukasa sheepishly smiled hoping it would pacify Senku. But the scientist just continued to pant, piercing the tallest male with an annoyed gaze, muttering 'not cute'. Amber eyes then blinked before kneeling down on the ground in front of the scientist. "...Um, Senku... are you...alright?"

 _'Am I alright? Am **I** alright!? Of course I'm not!',_ Senku internally rages, face red from embarrassment and anger. He just had one of the best orgasms ever, fondled by the strongest primate no less, he doesn't masturbate often and he's still horny! Senku sniffles as he tries to get up from the floor, both hands struggling to push his upper body up. 

Tsukasa had both hands held out to catch him in case he falls. But then Tsukasa just had to unconsciously curl his fingers inwards, putting pressure into the puppet again. Senku bit his lip to stop his moan as more tears gather at the corner of his eyes. He looks up pouting at Tsukasa, who looked sincerely concerned at Senku's well-being. 

Senku sniffled a sigh before dragging himself over and fell into Tsukasa's arms. One of his fists tried to pound on the taller man's chest hinting at his displeasure. "Darn you... take responsibility you...primate!"

"Huh?" Tsukasa blinks in surprise. "Senku... do you mean...?" At Tsukasa's unsure hesitance, Senku yanks the taller male's hair downwards, earning a yelp from Tsukasa. Senku brought the man's face to his level and he huffed, "I said, _take responsibility_ , you idiot." Glimmering red eyes squinted, "And I want the real thing! Put that away!"

Tsukasa gulped and quickly nodded at Senku's commands. The tallest male quickly removes the finger puppet from his finger, earning a breathy moan from Senku. Watching the scientist being so sensitive to even the tiniest of touch, Tsukasa carefully stored the Senku puppet inside of his sachets with the Tsukasa plush. He removed the sachets from his waist and placed it among the other items inside the observatory hut.

The strongest primate turns his attention back to Senku, "Senku... are you... really ok with this?"

"I'm ten billion percent sure with this. Don't make me repeat myself again," Senku groaned as he pounded another fist on Tsukasa's chest. "Just hurry up idiot, you started all of this!"

"Ok, ok." Tsukasa pacified and hauled Senku to sit in front of him, bringing his own lips to meet Senku's. Senku jolted at Tsukasa's sudden kiss, the taller male's lips gently nipping the scientist's mouth hesitantly. Senku can feel Tsukasa's tongue licking his lips before prodding for entrance. The young scientist could feel his face heating up and he opens his own mouth slightly to let the other have access inside. 

The feeling of having a foreign larger tongue roam around inside his own mouth sent jolts of pleasure down Senku's spine. The way that their tongues kept dancing around each other and how Tsukasa still managed to suck his tongue at the same time had Senku panting hard. Very soon, the young scientist's face was growing in heat and the lack of air filling his head. He clings hard to Tsukasa's makeshift yukata and tries to pat the taller male's shoulder, hoping Tsukasa will let him go for air.

Tsukasa didn't want to let Senku go ever. He just wants to keep sucking in that sweet, warm cavern and never let go. But as he feels Senku's patting had lulled to a stop, he knew he has to end this or the shorter male won't be able to continue on. Reluctantly, Tsukasa left Senku's mouth with a silvery trail of saliva between them, the young scientist breathing inwards and outwards rapidly while resting his head on Tsukasa's chest.

The strongest primate meanwhile trailed his hands downwards, one hand roaming down to one of Senku's nipples, his other hand going under Senku's tunic to scoop the previously ejected cum. The hand that was fondling with the nub on Senku's chest made the young scientist moan. Senku unconsciously hid his face within Tsukasa's neck due to embarrassment. His moaning sounds caused a tremor on Tsukasa's neck, making the taller male gasp with pleasure. Thinking this was a sign for Tsukasa to go further, the taller man pinched and lightly twisted Senku's nipple, causing the younger male to cry out.

Senku closed his eyes shut, hoping it'll also shut out the sensations. But that was a badly miscalculated move. He can actually feel Tsukasa's touches more intensely this way. Like how Tsukasa continues to tease his nipple before moving onto the other one and giving it the same treatment. Or how the taller male hiked the back of his tunic and caresses his butt. The feeling of a finger being pushed inside his entrance along with a squishy sound.

Ruby eyes opened in fright. This area was the very same place where Tsukasa had thrusted in him (The Senku finger puppet) and made him come _hard_. However, that one only had the sensation of pressure being applied to a spot and there was no physical matter inside him. This however, is a little different. He now actually has a physical object aka Tsukasa's long finger, prodding inside him. 

Senku's butt tries to escape from those teasing fingers, every time he tries to avoid them, the digits would pursue him and massage around his rim. The young scientist could feel his own cock bouncing back up in delight. The shorter male’s focus on the digit near his wet hole was taken away from a sudden hard pinch on one of his nipples. Senku let out a large gasp as Tsukasa rubbed both nipples with his single large hand. 

The strongest primate then gave a hard, painful twist on one of the nipples, causing Senku to cry out in pain. While that reduced the shorter male into a whimper, Tsukasa used the distraction it had on Senku and roamed his hand downwards to Senku's cock. The taller male started to stroke the scientist's manhood, his other hand leaving Senku's behind and bringing it up to scoop some precum off Senku. He then reinserted more cum into the younger male's cavern, sliding in another finger along the way.

Senku squirmed and moaned as another digit was added inside him. He panted as he could feel the fingers filling him up with more cum for lubrication purposes. The feeling of those slow, teasing fingers were twisting inside him to make sure all sides were lubricated. He tries to ignore the strange sensation and instead focused on his manhood being stroked by Tsukasa. But then he moaned aloud and flinched as Tsukasa's duo fingers hit something inside Senku. 

It was the same sensation when they did it with the puppet. "No-no..." Senku's face turned deep red. He started thrashing and tries to push Tsukasa away. But the strongest primate held him in place with a cheeky grin, "Ah, so it's this place then Senku?" Tsukasa said as he gradually thrusted quicker into that same area making Senku mewl. "Honestly, it's much bigger inside you compared to the finger puppet... so your sweet spot was harder to find it. How's that feeling Senku? Is it good?"

"Don't-aaahh! Ask...me that...you aahhh! ...Primate!" Senku tries to grit his own teeth to cut off his sounds. Dang it feels _so_ good! Senku tries to cover his moans in embarrassment with his two lone hands. But Tsukasa wants to hear more of that beautiful voice in ecstasy, so he stopped stroking Senku's manhood, earning a whine from the shorter male. With that one lone free hand, he grabbed both of Senku's wrists and removed them away from that beautiful voice.

And then focused back on increasing the spearing motion inside the shorter male's wet cavern, pulling his duo digits in and out, making sure to hit that spot each time. Senku thrashed again, the intensive heat concentrated into his nether region. His back arched once more as he came for a second time that day. White cum covered his own manhood, some droplets landed on Tsukasa's chest. 

"Nghh... no... more," Senku panted as some drool and tears trailed down his face due to the pleasurable activity. The scientist never felt this good before when it comes to masturbation, or in this case, sex. His thrills are usually from the scientific discoveries and experiments within his everyday life. Trying to calm his breathing and feel slightly lighter, he started to slide his head away from Tsukasa's chest. And then felt himself got pushed onto his back onto the floor.

"Huh?" Senku frowned at the sudden push from the strongest primate who is currently hovering above him. Confused ruby eyes squinted at the excited amber ones. "Tsukasa... what are you doing?" Senku felt a few strands of Tsukasa's hair tickling his cheek. His face goes red again.

"Hmm? Oh Senku, surely you didn't think that was the end, did you?" Tsukasa chuckled as he caressed Senku's cheek with one hand. His other went to Senku's cock, stroking more cum off the shorter male and bringing it back to his own manhood. The strongest primate tries to cover his own cock with Senku's cum, hoping it'll make the insertion process easier. 

"Nghh! What the- ngaaahhh... no-no... I... can't do it anymore!" Senku choked as Tsukasa was practically lying on top of him, Senku's own hands on either side of those broad shoulders. The young scientist wasn't sure where to place his hands, whether on Tsukasa's shoulders or back or head even. Before he could think anymore, Senku latched both of his hands onto Tsukasa's shoulders and cried out as the taller male pierces his slick hole with the larger manhood.

"Hmm... sure you can Senku. You took in my finger very well for the puppet. And then you got the real thing the second time. Surely, even just one more with a _bigger_ 'finger' is fine too, right?" Tsukasa cheekily grinned as he his own lips aimed for Senku's mouth to cut off the scientist's protests.

Senku felt SO full! The fingers couldn't compare! Senku grows hot from the kiss as he gets used to Tsukasa's cock size. The taller male hasn't moved yet, concentrating more on their kiss. Senku groaned as Tsukasa lightly bites at him, he tries to move his head away, wanting to complain. He moans louder as he pounded on Tsukasa's shoulders with his kitten-strength fists. He manages to get a gap from the kiss and complains, "M-move! Tsuka..."

"Hmm?" Tsukasa reluctantly leaves Senku's mouth, the shorter male immediately inhaled in vigorous patterns. "You're ok to go ahead, Senku?"

"YES! Just move it you primate!" Senku's ears turned red, turning his face to the side and placing an arm over his face. Tsukasa mentally coos at how adorably denying Senku is being, but decides he has enough of teasing the younger male. Plus, the strongest primate was also nearing his limit... "Ok, I'm ready, Senku."

"Hmm!" Senku moaned as Tsukasa started the rocking motion inside him. The scientist gasped at the different size and rough texture of the 'digit' currently touching on all sides of his inner walls. He mewled as Tsukasa had quickly found his pleasurable point quicker than before. His insides unconsciously clenched Tsukasa's manhood, making the taller male groan. Yet it wasn't enough to send the strongest primate to ecstasy yet.

Tsukasa just concentrated on gradually increasing his thrusting and circular motioning of his own hips, hoping it would bring more pleasure to the younger male below him. Senku's moans at every hit Tsukasa managed to make had made his own cock pulse and bulge bigger. This made Senku gasp, surprised at the fact that the taller male's cock can grow any larger. Exhilarated red eyes moaned and looked up at Tsukasa's pretty face, "...More."

"Hmm? What was that Senku?" Tsukasa was brimming with excitement but had thought he may have heard it wrong.

"...More! I want more!" Senku sobbed. "Take responsibility, you primate!" Senku's tearful face was the last straw that ignited Tsukasa's inner fire. The taller male swallowed his excitement and planted a kiss on the scientist's forehead. The strongest primate then hoisted both of Senku's thighs up onto his shoulders, the tip of his cock pushing and hitting the roof of Senku's insides. This earned a groan from Senku in which Tsukasa smiled. "Ok, Senku."

Tsukasa pulled out his cock, his tip stopping inside the rim area before spearing back into the shorter male. Senku gasped and mewled as the strongest primate pushed in unpredictable rhythms with force. Tsukasa could feel the friction of Senku's walls stroking hard around his cock. "Senku, Senku, Senku..." The taller male muttered, delighted at the warmth around his manhood and the feeling more heat pooling his area. His thrusting motion speeded up, to the point that Senku cannot feel a break in between each piercing.

Senku felt a cramp at his nether region, delightful gasps came after a string of heartful moans. Finally, the young scientist couldn't take the sensations anymore. He thrashed violently before letting out a loud mewl and came dry. His cavern clamped down on Tsukasa's cock and the strongest primate let out a loud groan as he came inside the shorter male. White cum sprayed and filled Senku's sensitive hole, the shorter male still twitching from his dry orgasm while Tsukasa continues to spurt more white streams of cum inside Senku.

Senku panted, trying to lull his excitement from all the vigorous activity he had just done. He's feeling _so_ full! The young scientist's ears turned red as he could feel the slosh and squishy liquid inside him. He moaned again as Tsukasa finally removed himself from him. The taller male gave off a happy aura as if he's just gotten to play with his favourite toy. Tsukasa curled a large arm around Senku, scooping the shorter male closer and let out a delighted sigh. He placed his head against Senku's forehead and smiling that 'shitty-grin' at the scientist.

And then Senku pulled Tsukasa's cheek. _Hard_. Tsukasa flinched. "Sen-Senku?"

" _So_... you _had_ a lot of fun, _didn't you_? Tsukasa?" Senku's eyes twitched as he gave the taller male a 'you wish you were dead' smile.

"Um...um... well... yes... Senku," Tsukasa sweated. "Um..."

"Tch," Senku huffed before placing a kiss on the taller male's cheek. Tsukasa's eyes widened at the action as he watches the red rosy blush on Senku's face. The young scientist buried his face under Tsukasa's chin and muttered as quietly as a kitten, "Take responsibility... you idiot."

"Sen-Senku!?" Tsukasa grabbed both of Senku's shoulders and shook the shorter male in excitement, making Senku's flushed face looking back at him, "Does... does that mean we are _'together'_ , together!?" 

But Senku looks to the side, ears burning, "...You nearly have the same intellect as I do, work it out yourself. Strongest Primate."

"Senku!" Tsukasa hugged the scientist tightly, who protests at being crushed and that he needs rest. The strongest primate places his forehead against Senku's once more as delighted amber eyes looked straight into shy, sparkling red ones. And then Tsukasa decided to drop the bomb, "So Senku, do you want to go for another round with the finger puppet again?"

"Ten billion percent NO!"

END

**Author's Note:**

>  **Afterword:** If you're wondering how this story came to be, just know that the company movic is officially making these real life finger puppets and plushies on some DCST characters. I heard they'll go on sale in March 2020. Plus, with the addition of some hilarious art/comic I’ve seen about the plushies/puppets ever since they’ve gotten announced, this idea had been born. And no, it makes no scientific or logic sense whatsoever. Hence this is why it’s just a fantasy fiction.
> 
> Do you like TsukasaSenku or SenkuTsukasa as a ship?  
> Would you like to chat about anything TsuSen/SenTsu with other fellow TsuSen/SenTsu fans?   
> [Click here to join us!](https://discord.gg/cDX456wCzD)


End file.
